Rivet Setting Device

ABSTRACT

What is proposed is a device for setting blind rivets which has a motor-actuated pulling device for pulling on the rivet mandrel. The pulling device comprises a disk spring which is initially stressed during the actuation of the pulling device. As soon as the force exerted on the rivet mandrel by the pulling device is sufficiently large such that the rivet mandrel breaks off as intended, the previously stressed spring suddenly relaxes and results in the part of the pulling device which engages on the rivet mandrel butting against a stop. As a result, this part of the pulling device then stops abruptly whereas the rivet mandrel is projected further. It is possible in this way for the rivet mandrel to be conveyed into a rivet mandrel container present in the housing without a user having to execute a particular operation for this purpose.

The invention is based on a blind riveting device by means of which the blind rivet is set by pulling engagement on a rivet mandrel of a blind rivet.

Blind rivets are those rivets which are inserted from the front side and are deformed without having access to the rear side of the location where the rivet is set. Deformation of the blind rivet to form a closing head on the rear side takes place by means of a rivet mandrel which is pulled. This can occur by means of manually actuated tongs or by means of blind rivet setting device having a drive. When setting the blind rivet, the rivet mandrel breaks off at a predetermined breaking point.

There is already known a blind rivet setting device in which a pulling device is actuated by means of an electric motor, which device pulls on the rivet mandrel of a blind rivet held in the device. In order to pull on the blind rivet, there is provided clamping tongs which have an inner cone and consequently load clamping jaws inwardly against the rivet mandrel. The clamping tongs surround a tube. As soon as the rivet mandrel is broken off, the user can tilt the device upwardly, with the result that the broken-off rivet mandrel slides downwardly through the tube under the force of gravity and is collected in a container (DE 4126602).

The object of the invention is to provide a blind rivet setting device which allows automatic removal of the rivet mandrel without further intervention of the user.

To achieve this object, the invention proposes a blind rivet setting device having the features stated in claim 1 and a method for setting a rivet. Further embodiments of the invention form the subject matter of subclaims.

The rivet setting device according to the invention comprises a pulling device which is actuated by hand or by a motor drive such that it pulls on the rivet mandrel. During the build-up of the pulling force, a compression spring is stressed. When the rivet mandrel breaks off at the predetermined breaking point intended for this purpose, the spring relaxes abruptly, leading to part of the pulling device butting against a stop, with the result that the part of the pulling device engaging on the rivet mandrel is stopped abruptly. Here, the rivet mandrel itself is released such that it maintains its movement and is propelled through the pulling device. It can then either be moved out of the device or be moved into a container present in the device.

Thus, during the setting of the rivet, the part of the pulling device engaging on the rivet mandrel is prestressed against a spring-elastic element which releases its energy again, which is stored during setting, when the rivet mandrel breaks off in order to move this part of the pulling device and the rivet mandrel in the pulling direction. Depending on where the spring-elastic element engages, this element can be a tension spring or a compression spring. Rubber bands or a spring-elastic plastic block are also conceivable.

In this way, after the rivet has been set by the device, the rivet mandrel itself can be removed from the holder and disposed of without the user having to care about this process himself.

According to the invention, provision can be made in a further embodiment for the pulling device to have a central tube extending in the axial direction and around which the individual components of the pulling device are arranged. The tube forms a through-passage for the broken-off rivet mandrel. It is ensured in this way that no transition points, gaps or projections against which the rivet mandrel could remain suspended during its movement are present in the path of the broken-off rivet mandrel.

To keep a firm hold on the rivet mandrel in order to set the blind rivet, according to the invention in a further embodiment the pulling device can have, in the region of its front end assigned to the holder for the blind rivet to be set, a clamping sleeve which, during pulling, charges the clamping jaws radially against the rivet mandrel.

For this purpose, the clamping sleeve can have, in the region of its front end, an inner cone which widens in the pulling direction and by means of which it bears against the outer side of the clamping jaws.

In order to be able to apply the clamping jaws with certainty against the rivet mandrel by means of the clamping sleeve, according to the invention in a further embodiment a compression spring can be provided which loads the clamping jaws in the axial direction in the direction of the end of the pulling device which is assigned to the holder for the blind rivet.

In particular, provision can be made in a further embodiment for the compression spring not to bear directly against the clamping jaws but against a jaw closer which for its turn bears against the clamping jaws. The jaw closer may be a sleeve.

The combination of compression spring and jaw closer loads the clamping jaws in a direction in which they are moved radially inwardly by the clamping sleeve when the clamping sleeve is pulled by the pulling device. In a further embodiment of the invention, provision can then be made for the clamping jaws and the jaw closer to be tailored to one another in such a way that the clamping jaws also experience a radial loading in the outward direction by means of the jaw closer. This serves not only to secure the application of the clamping jaws against the clamping sleeve, but also to release the clamping jaws from the rivet mandrel when the latter is broken off. This is because, when reaching the stop, the jaw closer then ensures that the clamping jaws are released from the rivet mandrel so that the latter continues its movement in a completely uninfluenced manner.

Clamping jaws and jaw closers can be tailored for example in such a way that the end face of the jaw closer assigned to the clamping jaws has a cone which engages on a correspondingly formed counter surface of the clamping jaws so as to load the latter radially.

In order to achieve a high spring force and thus a large acceleration over a short distance and thus also with a low space requirement, in a further embodiment of the invention provision can be made for the spring-elastic element compressed during pulling engagement on the pulling device to be designed as a disk spring, in particular as a disk spring assembly.

In order to provide a device which also operates maintenance-free with long-lasting use, according to the invention provision can be made in a further embodiment for the disk spring or the assembly of disk springs to be accommodated in a dedicated housing which surrounds the disk spring on all sides.

The drive for the pulling device may be, for example, an electric motor which engages with the aid of a transmission on the pulling device, in particular a spindle.

Since the invention provides a rivet setting device in which the removal of the broken-off rivet mandrel takes place automatically without the engagement of the user, provision can be made in a further embodiment of the invention for the device also to have a container for these broken-off rivet mandrels, in which container the rivet mandrels of a plurality of set blind rivets are collected.

Since, after being broken off at their predetermined breaking point, the rivet mandrels are moved through the tube contained in the pulling device, the invention proposes in a further embodiment to arrange in the rivet setting device a device by means of which a broken-off rivet mandrel can be conducted from the tube into the rivet mandrel container.

This device can consist for example in that a deflection device is moved behind the rear end of the tube.

A further possibility for realizing this device consists in that the rivet mandrel container is moved into the path of the rivet mandrel conveyed out of the tube, either by means of a pivoting movement or by a parallel displacement. Also possible is a combination of both movements.

In order to provide space for the rivet mandrel container during the introduction of the rivet mandrel into it, provision can be made according to the invention for the drive to be moved out of the position behind the tube, it being possible here for a pivoting movement or a parallel displacement or a combination of both possibilities to be provided as well.

Further features, details and advantages of the invention will become apparent from the claims and the abstract, the wording of both of which is incorporated in the description by reference, from the description below of preferred embodiments of the invention and with reference to the drawing, in which:

FIG. 1 shows a schematic section through the region of a rivet setting device according to the invention;

FIG. 2 shows the same section on a reduced scale;

FIG. 3 shows the same section after the stressing of the spring;

FIG. 4 shows the section after a further actuation of the pulling device;

FIG. 5 shows the section after the relaxing of the spring;

FIG. 6 shows the section after the release of the rivet mandrel;

FIG. 7 shows the section after restoring the initial state;

FIG. 8 shows a greatly simplified section through a rivet setting device;

FIG. 9 shows the section of FIG. 8 in another state;

FIG. 10 shows the section through a rivet setting device of another embodiment.

FIG. 1 schematically shows a front end of a rivet setting device according to the invention. A holder 2 for a blind rivet 1 is arranged in the front end. The blind rivet 1 has a rivet mandrel 7. The sleeve of the blind rivet 1 bears on the outer side of the holder 2, while the rivet mandrel 7 extends into the interior of the holder 2.

Arranged in the housing is a pulling device 4 which is composed of a number of parts. The pulling device 4 acts on a clamping sleeve 5 which is guided axially displaceably in the front end of the rivet setting device in a holder which surrounds it. The maximum forward movement, that is to say to the left in FIG. 1, is determined by the abutment of the end face of the clamping sleeve 5 against an inner shoulder. The front end of the clamping sleeve 5 has on the inner side a cone surface 6 whose cone, starting from the front end of the setting device, extends in the direction of the rear end, to the right in FIG. 1. Bearing against this cone surface 6 are clamping jaws 8 which are designed as individual elements and are arranged around the rivet mandrel 7.

The pulling device 4 is traversed centrally by a tube 9 which consequently forms a smooth uninterrupted through-passage 10. The tube 9 has an internal diameter which forms the through-passage 10 and which is greater than the diameter of the rivet mandrel 7 of a blind rivet 1 to be set.

The clamping jaws 8 are loaded in the direction of the front end of the rivet setting device by a jaw closer 11 which is designed as a sleeve. The end face of the jaw closer 11 which bears against the rear side of the clamping jaws 8 extends slightly conically, as does the end face of the clamping jaws 8 which faces the jaw closer 11. The jaw closer 11 is for its part loaded by a compression spring 12 which is arranged around the tube 10 and is supported on a further component.

An intermediate element 13 is fastened, in the present case screwed, in the clamping sleeve 5 and has an outwardly directed flange 14 at its end facing away from the front end of the rivet setting device. This flange 14, which has a planar end face, of the intermediate element 13 bears against an end face of a counterelement 15 of the pulling device 4, which counterelement for its part is screwed to the spindle 16, which can be seen on the right.

The counterelement 15 screwed to the spindle 16 has on the outer side of its flange 17 a thread onto which a housing 18 is screwed. Arranged in the interior of the housing 18 is a compression spring 19 which produces a compressive force between the inner side of the housing 18 connected to the counterelement 15 and the flange 14 connected to the clamping sleeve 5. The spring 19, which is designed as a disk spring assembly, thus presses the flange 14 of the intermediate element 13 against the flange 17 of the counterelement 15. The compression spring 12 is also supported on the intermediate element 13 and presses the jaw closer 11 by way of its cone surface against the clamping jaws 8.

The holder for the blind rivet 1 has a stop surface against which the front end of the clamping jaws 8 comes to a stop. When the clamping jaws 8 bear against this end face, the clamping jaws 8 have an inner space from one another which is greater than the diameter of the rivet mandrel 1.

When a rivet mandrel 1 is inserted into the device, the rivet mandrel 1 thus comes into the position represented in FIG. 1, which is also represented in FIG. 2 on a reduced scale. This is the initial position in order to set a blind rivet by pulling engagement on the rivet mandrel 1. Starting from the position represented, the pulling spindle 16 and thus the pulling device 4 are now actuated by means of a drive which is not shown (in the present case an electric motor—or alternatively for example by hand). The clamping sleeve 5 is moved to the right in FIGS. 2 to 7. Since the compression spring 19 is designed to be powerful, the clamping sleeve 5 is first of all moved synchronously with the spindle 16. The cone surface 6 on the inner side of the clamping sleeve 5 engages on the outer side of the clamping jaws 8 and moves them inwardly into engagement with the rivet mandrel 7. During further actuation of the pulling device, since the rivet mandrel 7 offers a resistance, the spring 19 is now first of all stressed until it lies in a block. This is represented in FIG. 3.

A further movement of the spindle 16 then leads to a synchronous further movement of the clamping sleeve 5 and thus of the rivet mandrel 7, which then in this way forms the rivet head (closing head). This further movement is represented in FIG. 4.

As soon as the pulling force is large enough, the mandrel breaks off at the predetermined breaking point, see FIG. 5. This results in the compression spring 19 relaxing. Whereas a spacing was produced between the flange 14 and the flange 17 when the spring 19 was deformed to a block, see FIG. 3 and FIG. 4, this spacing is now suddenly removed by the relaxing of the spring 19. The intermediate element 13 buts with the flange 14 against the flange 17. The clamping sleeve 5 can now no longer be moved further, but the momentum of the clamping jaws 8 which is still present and of the rivet mandrel 7 contained therein leads to these parts moving further in the pulling direction. During this further movement, the spring 12 surrounding the tube 9 is stressed, see FIG. 6, consequently pressing the jaw closer 11 against the clamping jaws 8 and moving them outward, with the result that they release the broken-off rivet mandrel 7. The rivet mandrel is projected through the through-passage 10 of the tube 9, whereas the clamping jaws 8 are moved back into their initial position in which a new blind rivet can now be inserted, as is shown in FIG. 7.

FIG. 8 shows the housing 20 of the rivet setting device in simplified form. On the left is the front end of the rivet setting device, with the holder 2 for a rivet mandrel being illustrated in simplified form. Arranged in the housing is a drive 21 (not explained in more detail) in order to shoot a rivet. This is not illustrated in detail. A switch which is actuated by a push button 22 is used to trigger the drive 21 and hence to set a blind rivet. A battery or an accumulator can be accommodated in the handle 23.

Also accommodated in the housing 20 is a container 24 for broken-off rivet mandrels 7. To ensure that the device does not become all too large, this container 24 is arranged below the drives 4, 21 and not at the rear end of the device. In order now to convey into the container 24 the broken-off rivet mandrels 7 projected out through the tube 9, provision is made in a first embodiment for the entire drive 21 to be able to be pivoted about a pivot point mounted between its ends. In this case, the rivet mandrel container connected to the drive 21 is likewise pivoted. A bent channel 25 which leads into the rivet mandrel container is likewise pivoted here such that it is in alignment with the end of the tube 9. This pivoting of the drive 21 and of the rivet mandrel container 24 is controlled in such a way that, when the rivet mandrel 7 is broken off, the channel 25 has the position illustrated in FIG. 9.

Whereas in the embodiment illustrated in FIG. 8 and FIG. 9, the drive 21 is pivoted, FIG. 10 shows an embodiment in which the entire drive 21 together with the rivet mandrel container 24 is displaced in parallel. In this case too, in the stage in which the broken-off rivet mandrel is projected through the tube 9, the channel 25 is arranged with its inlet end in the axial extension of the tube 9.

Of course, it would also be conceivable to displace the drive 21 axially in order thereby to form a larger interspace between the tube 9 and the drive 21, and to insert a deflecting device, for example similar to a channel 25, into this interspace, which device deflects the rivet mandrel into the rivet mandrel container 24.

A device for setting rivets is proposed which has a motor-actuated pulling device for pulling on the rivet mandrel. The pulling device contains a disk spring which is at first stressed during the actuation of the pulling device. As soon as the force exerted by the pulling device on the rivet mandrel is sufficiently large such that the rivet mandrel breaks off at the predetermined breaking point as intended, the previously stressed spring suddenly relaxes and causes the part of the pulling device engaging on the rivet mandrel to butt against a stop. As a result, this part of the pulling device then stops abruptly, while the rivet mandrel is propelled further. It is possible in this way for the rivet mandrel to be conveyed in a rivet mandrel container present in the housing without a user having to carry out a particular operation for this purpose.

The rivet setting devices described hitherto have a drive 21 in order to shoot the rivet into, for example, two sheets and a drive 4 in order to pull on the rivet mandrel and to form a closing head. In a rivet setting device of this type, the drive 21 must first of all be arranged axially with respect to the holder in order to shoot the rivet axially, and then either the drive must be moved out of this axis, for example translationally or rotationally, in order to provide space for the channel 25, or a deflecting device, for example a channel 25, must be moved into this axis in order to guide the rivet mandrel moved in the pulling direction into the rivet mandrel container.

In a variant to the rivet setting devices of FIGS. 8 and 10, the drive 21 is absent, with the result that a rivet setting device is provided by means of which the rivet can only be set, that is to say it is only possible to pull on the rivet. A channel 25 can then be arranged in a stationary manner in the pulling direction behind the pulling device 4 in order to guide the broken-off rivet mandrels into a rivet mandrel container. 

1. A rivet setting device, with a housing (20), a holder (2) arranged in the housing (20) for a rivet (1) to be set, a pulling device (4) arranged in the housing (20) for pulling engagement on a rivet mandrel (7) of the rivet (1) arranged in the holder (2), a drive for the pulling device (4), and with an, in particular compressed, spring-elastic element (19) which engages on the pulling device (4) and is elastically deformed during the pull engagement, which element is relaxed during the breaking-off of the rivet mandrel (7) in order to move a part of the pulling device (4) with the rivet mandrel (7) in the pulling direction.
 2. The rivet setting device as claimed in claim 1, wherein the pulling device (4) surrounds a central tube (9) which extends in the axial direction and in which the rivet mandrel (7) is guided.
 3. The rivet setting device as claimed in claim 1, wherein the pulling device (4) has, in the region of its front end assigned to the holder (2) for the blind rivet (1) to be set, a clamping sleeve (5) which, during pulling, charges the clamping jaws (8) radially against the rivet mandrel (7) and/or a release mechanism (11) which radially moves the clamping jaws (8) away from the rivet mandrel (7) when the rivet mandrel (7) is broken off.
 4. The rivet setting device as claimed in claim 3, wherein the clamping sleeve (5) has, in the region of its front end, an inner cone (6) which widens in the pulling direction and by means of which it bears against the outer side of the clamping jaws (8).
 5. The rivet setting device as claimed in claim 3, wherein, in order to load the clamping jaws (8) in the axial direction, a compression spring (12) is provided which acts in particular on a jaw closer (11) bearing against the clamping jaws (8).
 6. The rivet setting device as claimed in claim 5, wherein the clamping jaws (8) and the jaw closer (11) are tailored to one another in such a way that a loading of the jaw closer (11) by the compression spring (12) leads not only to an axial loading of the clamping jaws (8) against the clamping sleeve (5) but also to a smaller loading of the clamping jaws (8) in the radially outward direction.
 7. The rivet setting device as claimed in claim 1, wherein the spring-elastic element (19) is a disk spring, in particular a disk spring assembly, which is advantageously arranged in a housing (18) which surrounds it.
 8. The rivet setting device as claimed in claim 1, with a rivet mandrel container (25) arranged in the housing (20) for the broken-off rivet mandrels (7) of a plurality of set rivets.
 9. The rivet setting device as claimed in claim 11, with a device for introducing a broken-off rivet mandrel (7) into the rivet mandrel container (25), which rivet mandrel is moved through the tube (9).
 10. The rivet setting device as claimed in claim 1, with a drive (21) for setting the rivets, wherein the drive (21) is arranged in particular in such a way that it can be moved, in particular pivoted or displaced, out of the axial expansion of the tube (9) passing through the pulling device (4).
 11. The rivet setting device as claimed in claims 13, wherein an inlet can be moved into the rivet mandrel container (25) in the axial extension of the tube (9) passing through the pulling device (4).
 12. The rivet setting device as claimed in claims 8, with a deflecting device for deflecting into the rivet mandrel container (25) a broken-off rivet mandrel (7) moved through the tube (9), wherein the deflection device is designed to be movable between the tube (9) and the drive for the pulling device (4).
 13. A method for setting a rivet, comprising the following steps: a rivet mandrel (7) of a rivet is introduced into a rivet setting device, pulling is carried out on the rivet mandrel (7) by means of a pulling device (4) of the rivet setting device, at the same time as the pulling, a spring-elastic element (19) engaging on the pulling device (4) is stressed, pulling is continued until the rivet mandrel (7) breaks off, after the rivet mandrel (7) has broken off, a part of the pulling device (4) with the broken-off rivet mandrel (7) is moved in the pulling direction by relaxing the spring-elastic element (19).
 14. The method as claimed in claim 13, wherein after the method step 13.5 the rivet mandrel (7) is released by the pulling device (4).
 15. The method as claimed in claim 13, wherein the rivet mandrel (7) is moved into a rivet mandrel container (25) after the method step of claim
 14. 16. The method as claimed in claim 13, wherein the part of the pulling device (4) moved in the method step 13.5 is braked, in particular by means of a stop, before or after the method step of claim
 15. 